I have a 1981 Jeep C-J 5 with the "Iron Duke" 4cly engine. The Jeep has only on road miles and was used as a daily driver for about five years and now only gets driven every month to keep the fluids moving.

I am thinking about putting money into it and don't know if it would be worth putting a new engine in it or just have the old one rebuilt. The thing never goes over 55mph and is very sluggish going up hills. I have had it tuned up every year and the oil changed but the carb just will not give it the gas to accelerate.

Any thoughts?

Thought of replacing the carb first? Maybe that is your only problem. That would be a much faster and cheaper fix than rebuilding the motor. If that doesn't get it then you will at least have a new carb to add to a new or rebuilt motor.

So, where are the pictures?

81 was the height of the EPA BS making every car on the market down right stink. This was especially true of the last of the carberated vehicles. The worst carbs ever made was 1980 and 81. They were transition carbs to fuel injection and even had aneroids (mechanical altitude sensing device) inside the carb as well as enough air pollution crap on the engine to choke a horse and it did.

That's probably a I4 2.5 one barrel putting out a whopping 105 hp. The fuel injected models only picked up 12 hp.

On the bright side, the CJ5 is still exceptionally popular with off road enthusiasts and even a crapped out CJ5 that performs well sells anywhere from $4,500 to $6,500. Man, that's awfully good for a 81. The Korean and Vietnam war era Jeep, it was pretty much on its way out and yours being a carb one of the last of its kind.

It would totally blow me away if you told me all the air pollution crap is still on there. It was quite common on vehicles to yank that crap as soon as it started causing continual repairs to keep it up. It was also very common for folks to do that and not re-tune the engine thinking because it was running smoother it was fine but really losing some Hp and fuel economy.

The bad news is because it was AMC, it had two carboraters for that year. One was a AC Rochester, a total piece of junk (I ought to know my company made part of the junk). The good news is, there was also the Carter. The good news is a Carter YF just might bolt right in there which was the standard one barrel up to 1973.

Here's some YF manuals if you are interested in seeing if the bolt pattern is the same. Carter YF

Needless to say, the Carter YF has zero pollution crap and because they are a carter a snap to install and tune. Carters are very simple carbs compared to Holley even let alone Rochesters which for known for a gazillion parts. Since the 81 still used a distributer even if it was an early electronic (which included carb) if it bolts up the change could be as simple as a Mopar Performance electronic ignition kit (includes wiring) and a carburetor. For those of us who do this type stuff, that's pretty easy even for a worse case scenario. I don't know what these electronic ignitions go for now, but they're not expensive, real simple, little potted box that screws onto the fire wall. Last time I think I paid, $45 but its been a few years. What you are doing basically is taking it back to the 73 model.

Another thing to look for, is the pickup on the distributor if it has one. They can make the engine run like hell or even cut out at times and folks scratching their heads for weeks. When you find out, its a low cost part and very quick change like minutes its almost disappointing. If there are no points then its electronic even if it does have a rotor button and distributor cap.

Because the 2.5L was in production for years, there's all kinds of parts for it still available, so a rebuild totally not out of the question though I'd definitely skip the air pollution crap.

Two ways to make your Jeep desirable for resale. One is taking it back to factory original. That does not include tires and since Jeeps are Jeeps kind of hard for it to not fit that category compared to a car. Show car standards are two major modifications allowed to still be in the original category not modified. Basically you can do anything to the Jeep as long as the VIN numbers match up. The other way is modified in which the V8s are the most desirable. Probably the most popular for the CJ was the 304. That change out would require an entire new drive train, engine, tranny, transfer case, exhaust, and axles. A hopped up 304 with performance intake, hedders, etc. is very popular.

From a collectible standpoint the strength of the Jeep and a big part of it allure is its simplicity.

I hope this helps.

Tj

If it were me and I was keeping it I would put in either a Buick 3.8L V6 or a Chevy fuel injected 4.3L V6 and a GM hydr. 350 tranny.

Knowing what you'll be dealing with in getting it to pass DEQ, I'd say follow Tj's advice. Those Carter carburetors are much easier to screw with, if you can replace a factory rochester carb with one, I'd jump on it. Those 4cyl CJ's are a blast, they just sip the gas, and will still go just about anywhere that doesn't require massive horsepower.

Good luck.

i don't know much about engines and stuff but if you are going to do it, do it right.

this sounds like it will be a fun project for you.

THANKS for all the great advice! I will check it out and replace the carb with one of the ones you recommend. If this works I will let you know. I am still learning how to add photo's. Found instructions on using Photobucket so I should be able to add photos.

stuff a 401 AMC in her...that will make you smile,LOL

Recomment a factory rebuild...usually get best warranty. Just a thought...I been there and done several differnent ways...best luck I ever had was with factory rebuild!

Ditch the 4 banger and swap to a newer 4.0L or something. The AMC and Jeep I6's were pretty stout, and should be a straightforeward swap considering it was an option on your truck.